Lining is a process consisting of placing layers of reinforced composite in the form of linings on a mold. A very widely used example of a composite in the aeronautical industry is the preimpregnated composite, a mixture of fibrous reinforcement and polymer matrix used for manufacturing composites such that they can be stored for subsequent use.
It may be in the form of a sheet, lining, tow or fabric form. For thermosetting matrices, the resin is generally partially cured or is taken by means of another process to a controlled viscosity, called B-stage. Added elements, such as flame catalysts, inhibitors and retardants, can be added to obtain specific features in the final use and to improve the process, storage and handling features.
In this process, the linings are not randomly arranged, but they are generally arranged or placed in certain directions, specifically at 0°, 90°, 45° and −45°. The number of layers (thickness) and the arrangement of the linings in certain directions or in others are determined according to the nature and magnitude of the stresses that the piece will support at each point.
There are two types of lining: planar and curved, according to whether the surface being lined is planar or curved, respectively.
The lining process can be done manually or automatically. Machines performing lining are basically of two types:                Lining machines: lining on planar or slightly curved surfaces.        Fiber positioning machines: lining on surfaces with a large curvature on which lining machines cannot line.        
There are mainly two criteria determining whether a part is lined manually or automatically: the material used and the dimensions of the piece.
One material used, among others, for lining is the preimpregnated material. This material is sticky and its handling is not simple. Manually adapting the preimpregnated lining to a straight line contained on a plane is not very complex, however adapting such lining to a curve is very complex since this material does not deform by itself, so the operator must constantly put pressure on the lining so that it deforms and adapts to the desired curve, with the added difficulty that the lining is sticky. Furthermore, if the number of linings to be placed is very high, the complexity ostensibly increases.
This invention comes about from the need to line a piece of the new Airbus A380 airplane, which is an ellipse carried out on a plane, resulting from the section in a cylinder with an inclined plane.
In a manufacturability test, it could be seen that the manual lining of this mold was very complex given the geometry of the curve to be lined and the high number of layers to be arranged.
The lining was also carried out with a lining machine. In these cases, given the size of the mold, a larger area is first lined, and then it continues to a cutting operation to define the curve in question. This process is not cost-effective since the machine is not being used optimally.
This invention aims to overcome the difficulties mentioned for the manual lining of said piece and the non cost-effectiveness of lining or fiber positioning machines.